At a Glance
Why Get Tested?
To detect and monitor the activity of inflammation as an aid in the diagnosis of the underlying cause
When to Get Tested?
A blood sample drawn from a vein in the arm
Test Preparation Needed?
The Test Sample
What is being tested?
ESR is an indirect measure of the degree of inflammation present in the body. It measures the rate of fall (sedimentation) of erythrocytes (red blood cells) in a tall, thin tube of blood. Results are reported as how many millimetres of clear plasma are present at the top of the column after one hour. Normally, red cells fall slowly, leaving little clear plasma. Increased blood levels of certain proteins (such as fibrinogen or immunoglobulins, which are increased in inflammation) cause the red blood cells to fall more rapidly, increasing the ESR.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in your arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.